// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Linux specific implementation of VideoCaptureDevice.
// V4L2 is used for capturing. V4L2 does not provide its own thread for
// capturing so this implementation uses a Chromium thread for fetching frames
// from V4L2.

#ifndef MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_LINUX_H_
#define MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_LINUX_H_

#include <stdint.h>

#include <string>

#include "base/files/file_util.h"
#include "base/files/scoped_file.h"
#include "base/macros.h"
#include "base/threading/thread.h"
#include "media/capture/video/video_capture_device.h"
#include "media/capture/video_capture_types.h"

namespace media {

class V4L2CaptureDelegate;

// Linux V4L2 implementation of VideoCaptureDevice.
class VideoCaptureDeviceLinux : public VideoCaptureDevice {
public:
    static VideoPixelFormat V4l2FourCcToChromiumPixelFormat(uint32_t v4l2_fourcc);
    static std::list<uint32_t> GetListOfUsableFourCCs(bool favour_mjpeg);

    explicit VideoCaptureDeviceLinux(
        const VideoCaptureDeviceDescriptor& device_descriptor);
    ~VideoCaptureDeviceLinux() override;

    // VideoCaptureDevice implementation.
    void AllocateAndStart(const VideoCaptureParams& params,
        std::unique_ptr<Client> client) override;
    void StopAndDeAllocate() override;
    void TakePhoto(TakePhotoCallback callback) override;
    void GetPhotoCapabilities(GetPhotoCapabilitiesCallback callback) override;
    void SetPhotoOptions(mojom::PhotoSettingsPtr settings,
        SetPhotoOptionsCallback callback) override;

protected:
    virtual void SetRotation(int rotation);

    const VideoCaptureDeviceDescriptor device_descriptor_;

private:
    static int TranslatePowerLineFrequencyToV4L2(PowerLineFrequency frequency);

    // Internal delegate doing the actual capture setting, buffer allocation and
    // circulation with the V4L2 API. Created and deleted in the thread where
    // VideoCaptureDeviceLinux lives but otherwise operating on |v4l2_thread_|.
    scoped_refptr<V4L2CaptureDelegate> capture_impl_;

    // Photo-related requests waiting for |v4l2_thread_| to be active.
    std::list<base::Closure> photo_requests_queue_;

    base::Thread v4l2_thread_; // Thread used for reading data from the device.

    DISALLOW_IMPLICIT_CONSTRUCTORS(VideoCaptureDeviceLinux);
};

} // namespace media

#endif // MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_LINUX_H_
